Tangent adjusting means



A. LANGSNER TANGENT ADJUSTING MEANS Oct. 4, 1938.

Filed April 16, 1938 3 Sheets-Sheet l g NW INVENTOR.

ATTORNEY5.

Oct. 4, 1938. A. LANGSNER TANGENT ADJUSTING MEANS Filed April 16, 1933 5 Sheets-Sheet 2 INVENTOR W ATTORNEYS Oct. 4, 1938. A. LANGSNER TANG-ENT ADJUSTING MEANS s Sheets-Sheet 3 Filed April 16, 1933 J51 J77 J INVENTOR.

fldafih/layinel' ATTORNEY5,

Patented Oct. 4, 1938 UNITED res ATENT OFFICE TANGEN T ADJUSTING MEANS aware Application April 16, 1938, Serial No. 202,426

38 Claims.

My invention relates in general to precision adjusting devices and has more particular reference to means for adjusting transits, levels and similar instruments used in surveying, the present application comprising a continuation in part of my copending application for United States Letters Patent on improvements in Transits, Serial No. 757,849, filed December 17, 1934.

An important object of my present invention resides in providing an adjustable support, as in a transit, comprising frame elements interconnected for relative angular movement and including mechanism, such as tangent adjusting means, for adjusting the relative angularity of the frame elements and comprising parts designed to cooperate in excluding dirt and other foreign matter from the adjusting mechanism; a further object being to form the component parts to facilitate assembly thereof, to strengthen the same against mechanical damage, and to impart a pleasing appearance in the assembled device.

Another important object is to provide tangent adjusting means for angularly adjustable frames, comprising adjustable pintles on one frame and a projecting finger on the other, wherein the pintles are carried in a mounting formed to provide a chamber in position to receive the projecting finger whereby the tangent adjusting mechanism may cooperate with the projecting finger entirely within the housing in order to enclose and protect the parts from mechanical damage and deleterious foreign matter, such as atmospheric dirt and moisture; a further object being to arrange the projecting finger in position extending into the housing through a lateral opening therein and to provide, in association with the projecting finger, means forming a cover for closing the opening at all times, while permitting movement of the projecting finger within the housing in response to operationof the pintles.

Another object is to form a tangent adjusting pintle mounting as a housing for the exclusion of deleterious foreign matter, and to protect the same from mechanical damage.

Another important object is to mount the adjusting pintles in the opposite ends of an elongated shell forming an enclosing housing, the housing having an opening in a side thereof through which the finger may extend into the housing, said opening having a defining edge forming a flat seat, and the finger having associated means forming a cover in position to engage the seat and seal up the opening. Another object is to curve the seat on the arc of a circle and provide a correspondingly curved cover. A further object is to interpose a sealing gasket between the seat and the cover.

Another important object is to arrange the pintle mounting housing as an integral part of 5 one of the relatively adjustable frames. A further object is to arrange the cover as an integral part of one of the relatively adjustable frames.

A still further object is to form the seat with a socket mounting therein for the projecting finger. 10 Yet another object is to provide for removably mounting the finger, as by threading the same in the socket. A further object is to form the finger with a hardened insert forming a pintle bearing. Another object is to form the finger mount as a cover for the pintle housing.

Another object is to arrange tangent adjusting means for angularly adjustable frames, comprising cooperating pintle and finger elements, wherein one of the elements is mounted on pro- 20 jecting portions of a clamp adapted to be secured in any desired angular relationship on one of the adjustable frames, the other element being carried by the other frame; a further object being to arrange the clamp with operable means, for securing the same in clamped position in a desired angular relationship on its associated frame, the operable means extending in the projecting portions of the clamp adjacent the clamp mounted element of the tangent adjusting aSl3 sembly, so that the clamp and the tangent ad justing means may be operated from closely adjacent positions in the assembly.

Another important object is to form the pintle mounting and housing means as an integral part 5 of a clamp.

Another important object'is to mount the finger element on a clamp adapted to be secured on one relatively adjustable frame, with the pintle housing on the other frame.

Another important object is to provide an improved manually-operable head for actuating stems in tangent adjusting means, clamps and the like having movable stems supported in usually sleeve-like stem mounts, by forming the head with a cylindrical socket for receiving a cylindrical portion of the stem mount and forming therewith a substantial bearing for supporting the head on the stem mount to protect and enclose the end of the stem projecting from the stem mount and to prevent stem bending as a result of forces applied accidentally on the actuating head.

Another important object is to provide, in de-; 55

vices having an adjustable stem or pintle extending in a sleeve with an end of the stem projecting outwardly of the sleeve, the combination,

with the stem and sleeve, of a manually operable head on the projecting end of the stem for actuating the stem in the sleeve, the head having a socket snugly embracing the end of the sleeve to an appreciable extent whereby to support the head on the sleeve substantially against screw bending movement, and thus protect the stem from mechanicaldarnage as from screw bending forces applied accidentally on said head.

A further object is to provide means for sealing a tangent clamp against ingress of deleterious matter to the bearing means by which the clamp is mounted on its associated frame element.

Another object is to provide an improved dust, moisture and dirt-proof tangentclamp construction embodying in combination an upper and a lower clamp arrangement of the'general character employed in transits, wherein both clamps are adapted to be adjustably clamped on a common intermediate frame, one clamp affording tangent adjustment in cooperation with a support frame carrying the intermediate'frame, and the other clamp aifordingtangent adjustment in association with a mounting frame supported on the intermediate frame and carrying a sighting device.

Another object is to provide an improved tangent clamp construction for adjusting a sighting device tiltingly about a horizontal axis.

Another object is to provide an improved tangent clamp construction for adjusting a telescope rotatably about a vertical axis.

Another object is to provide improved tangent adjusting mechanism structure adapted for use in association with the compass plate of transits;

for use in association with the leveling frame and for use in levels and the like.

These and numerous other objects, advantages and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in connection. with the accompanying drawings, discloses preferred embodiments of the invention.

Referring to the drawings,

Figure 1 is a perspective view of a transi comprising tangent clamp structures and tangent adjusting mechanism embodying my present invention;

Figure 2 is an enlarged sectional view taken substantially along line 2-2 in Figure l;

Figures 3, 4 and 5 are perspective views of tangent clamps contained in the transit assembly shown in Figure 1;

Figure 6 is a fragmentary sectional view taken substantially along the line-66 in Figures 3, 4

and 5;

Figures '7, 8 and 9 are sectional views, respectively, taken substantially along the lines 'l'l in Figures 3, 4, 5 and 8, along the lines 88 in Figures 1, 2, 3 and 5, and along the lines 9-9 in Figures 1, 2 and 4; V

Figure 10 is a perspective view showing a modified arrangement of the tangent adjusting means illustrated in Figures 4 and 9;

Figure 11 is a perspective view, partially in section, showing a modified arrangement of the ures 1 and 13 of the drawings.

tangent adjusting means shown in Figures 3, 7 and 8;

Figure 12 is a sectional view taken along the line l2-!2 in Figure 11; and

Figures 13 and 14 are perspective views of tangent clamp and adjusting means embodying 'my invention as applied in a level.

To illustrate my invention, I have shown precision measuring instruments for, use in surveying, and comprising tangent clamp structures and tangent adjusting mechanism embodying the features of my present invention. be obvious, however, that the invention is not necessarily restricted to clamps and adjusting means embodied specifically in surveying instruments. On the contrary, many features of the present invention may be utilized to advantage in any assembly of relatively movable frames requiring relative angular adjustment. For the purpose of exemplification, however, I have illustrated the invention as the same may be embodied in transits, levels and. other surveying instruments, and to this end I have shown a transit 2i and a level 23, respectively,in Fig- The transit and level both comprise adjustable support means for mounting a sighting device, which, ineach of the illustrated embodiments, comprises a telescope 25, and for accurately adjusting the angularity of the sighting device in order to'train the same upon sighted objects.

The transit 2|, of course, provides for adjusting the sighting device to accurately sighted position and is formed to measure and indicate the adjusted position of the sighting device in terms of its displacement from a predetermined datum position.

' Both the transit and the level comprise a support element or base 21 provided preferably with means 28 for mounting the same as on a supporting tripod (not shown). The support element 21 comprises a leveling screw plate on which is tiltably mounted, as by means of a ball and socket connection 29, a tilting frame 3| having a sleeve-like portion 33 connected at one end on the base 21 by means of the ball and socket connection 29. The frame 3|, has a plurality of arms 35 preferably integral with the sleeve portion 33 and extending radiallyv outwardly thereof in position carrying leveling screws 3?. These leveling screws are threaded in openings formed in the extremities of the arms 35 which are preferably split at said openings, as at 39, and provided with clamping screws ll to adjust tightness of the split arm portions;

on the leveling screws.

- The leveling screws comprise threaded stems and project above and below the arms 35, the stems being formed at their lower ends with balls 43 adapted for reception in sockets 45 formed on or carried by the base 21 at or near the peripheral edge thereof. The sockets 45 preferably comprise cup-shaped elements having their bottoms secured to the base 21, the sides of the cup-shaped elements being peened at their upper edgesaround the balls 43 in order to secure the same in these sockets.

The leveling screws carry substantially disklike portions 41 which extend outwardly of the screws intermediate the base 21 and the frame 3|, and the peripheral edges of the disks 4'! are or may be knurled as shown to facilitate manipulation of the same in adjusting the tilted relationship of the frame 3| on the base plate 21.

, Dust caps 49, preferably comprising spun It will sheet-metal shells, may be secured on the arms 35 in position to enclose the upper projecting ends of the screws 31.

The sleeve-like portion 33 of the frame 3| provides a journal for rotatably supporting means on which the sighting device 25 is mounted, and it will be understood that the leveling screws 31 and cooperating elements are for the purpose of adjusting, to a vertical position, the axis of the sleeve 33 in conditioning the instrument for operation of the sighting device.

In the embodiment comprising a transit, as shown in Figures 1 and 2 of the drawings, the sleeve 33 comprises a journal which rotatably receives and supports a sleeve-like element 5! comprising a clamp mounting frame, which, in turn,

rotatably receives and supports a spindle 53 so that the spindle 53, sleeve 5!, and journal 33 have coaxial concentric relationship and are each relatively rotatable with respect to the other. The spindle, sleeve and journal also are preferably tapered, sothat the parts may be held in assembled relationship, as by means of the holding nut 55 applied on the projecting end of the spindle in position riding upon the lower ends of the sleeve and journal.

The lower end of the journal is preferably threaded to receive a spherical nut 51 and holding means comprising a nut 59. The spherical nut 51 comprises a part of the ball and socket connection 29, the other part of which comprises a member 6| having a dome-like portion forming a shell receiving the nuts 51 and 59, and a plate-like portion secured to the base 21. The nut 59, at its periphery, carries a resilient -sealing gasket 53 in position wiping upon the inner surfaces of the dome 6| to seal the ball and socket connection against access by deleterious foreign material.

The journal 33 also is threaded to receive an annular skirt 65 preferably of sheet-metal and having curled marginal edges enclosing an annular sealing gasket 61 adapted to wipe upon the outer surfaces of the dome 6| to'prevent deleterious foreign matter from reaching the ball and socket connection through the opening in the top of the dome through which the journal 33 extends.

The'upper end of the sleeve 5| projects upwardly of the journal 33 and is provided with a head 69 which overlies the upper end of the journal 33, the outer surfaces of the upper end of which provide cylindrical surfaces. The head 69 is formed with a seat receiving a collar H which is secured in place on the head in any suitable manner, as by fastening screws 13. The collar H has an annular flanged portion TI, the peripheral edges of which are preferably beveled, as illustrated. This collar H has a cylindrical portion 'l5 snugly embracing the outer cylindrical portions of the upper end of the journal 33, the outer end of said portion 15 riding on an upwardly-facing, annular shoulder or seat 19 formed in the outer surfaces of the journal 33, said shoulder being extended outwardly of the lower edge of the portion 15 in position facing the under side of the flange 11.

The head 69 also provides an annular, downwardly-facing seat or shoulder 8| which faces the upper surface of the flange TI, and has a cylindrical surface 83 forming an annular seat in the head adjacent the shoulder Bi and between it and the facing surface of the flange TI. The collar H likewise forms a cylindrical seat 85 in the outer surfaces of the portion 15 and extending'between the shoulder I9 and the facing surface of the flange TI.

The spindle53 has a head 89 extending outwardly of and-above the upper end of the sleeve 5|." On this head is mounted and secured, as by means of the fastening screws 9 I, a compass plate 93 having a dependent marginal flange 95Land carrying a compass 91 enclosed in a casing mounted on the plate.

The compass comprises a compass ring 99, concentric with respect to the axis of the spindle, and an indicator element llllpivoted, as at lB3,for rotation about the axis of the spindle. The com pass also preferably includes operable mechanism, indicated at l 95, comprising a stem extendingin a sleeve-like frame portion I04 and provided with a manually-operable head I96 on said sleeve-like portion for selectively disabling the pointer element'and conditioning it for operation, and also for adjustably turning the index ring 99.

The head 69 0f the sleeve element5l is provided upwardly of the shoulder 8| with an annular seat 'llJ'l adapted to receive and support an annular cover plate I99 which is anchored at its inner portions on the seat ID! in any suitable fashion, as by the fastening elements III. Thecover plate l09 extends outwardly of the seat l9? and underlies the compass. plate 93." It has an upwardly extending flange H3 extending within and bearing upon the marginal flange 95 of the compass plate.

A resilient annular gasket H5 is preferably interposed between the flanges 95 and H3 in order to seal the space therebetween, the gasket preferably being received in a peripheral groove formed in the flange H3. The flange H3 also is formed to provide an upwardly-facing scale surface l l3 visible upwardly of the compass plate through suitable openings provided therein. These openings may be hidden by suitable covers 4 l9 adapted to be lifted to the position illustrated in Figure 1, when it is desired to View the scale surfaces H1. The plate 199 may be accurately adjusted on the frame 69 by means of the aligning screws H2 disposed radially and in spaced relationship in the seat IN to make flange H3 exactly concentric with the axis of the sleeve 5!.

The compass plate may also carry one or more liquid levels- IZl in order to adjust the same inhorizontal position in conditioning the transit for use.

The .compass plate also carries a frame comprising spaced uprights l23 which are provided with journals, as at 525, in which is mounted a tilting frame or axle I21 on which the sighting device or telescope is carried. One of the frame elements and the axle may be provided with cooperating scale means preferably enclosed by a guard I29, said cooperating scale means being adapted to indicate the tilted condition of the telescope with respect to the compass plate.

It will be noted that the frame element comprising the sleeve 5! is freely rotatable with respect to the support frame 3|; that the frame comprising the spindle and the compass plate is freely rotatable with respect to the sleeve ele- 'ment 5i and the parts mounted thereon; and

that the sighting device is freely rotatable and tiltable with respect to the compass plate and its supporting frame. The parts may thus be freely adjusted with respect to each other.

In using the transit, however, it is necessary to clamp or anchor the various parts in relatively adjusted position and also to provide meansfor relatively turning the same by slight 'rying telescope supports MI.

amounts and accurately in order to precisely align the sighting device upon anobjective, and to this end tangent clamps are employed, there being a clamp I3I cooperatively associated with the tilting frame I21 and the supports carrying the same from the compass plate, a clamp I33 cooperatively associated with the compass plate and the clamp mounting sleeve element or frame and a clamp I35 cooperatively associated with the clamp-carrying frame 5| and the leveling frame 3I.

vThese clamps I 3I, I33 and I35 are preferably ofv like construction, the same being illustrated, respectively,'in Figures 3, 4 and 5 of the drawngs.- Y

In the level illustratedin Figure 13, the same comprising a so-called Y level, the sighting de vice or telescope is secured in a frame, preferably comprising an elongated plate I39 car- The frame I39 is provided with a spindle similar to the spindle 53 in the embodiment illustrated in Figure 2, which spindle is journalled directly in the sleeve-like portion 33 of the leveling frame 3I. The frame I39 is thus freely rotatable with respect to the ,support frame 31 in order to orient the sighting device about the axis of the sleeve 33. To secure the frame I39 in the sleeve, and at the g same time to provide for accurately adjusting the relative angularity of the parts, a tangent clamp I31 is provided, said clamp preferably having a construction and arrangement similar to that of the clamps I3I, I33 and I35 in the transit embodiment. V

The clamps I3I, I33, I35 and I31 comprise frames, each providing an annular clamping portion I43, and tangent adjusting means I in spaced relationship with respect to the annular clamping portion, the parts being interconnected to form 9. preferably integral structure. The inner surfaces of the clamping portions I43 in each instance are formed for reception in a corresponding clamp seat, and the opposed side surfaces of the clamping portions are provided each withan annular sealing gasket I41 preferably comprising a felt gasket extending in a suitable groove formed in the face of the clamping portion.

The inner surface of the clamping portion is also preferably cut away, as at I49, to form a preferably semicylindrical seat for a clamping element I5I, comprising a clamping block having semicylindrical surfaces adapted to extend in the seat I49, and a clamping surface which may be conveniently formed to continue the curvature of the inner surface of the clamping portion.

Opposite the seat I49 the clamping portion I43 is formed with an outstanding sleeve I53 which contains a block connected stem I55, and I provide means for actuating the stem I and its connected clamping block from the outer end of the sleeve-like extension I 53. To this end, the inher, surfaces of the sleeve, at least the outer portions thereof, are'threaded to receive a screwthr'eadcd element I51, which may be an extension of the stem I55 or may be separately formed, the

outer end of which projects from the end of the sleeve and is formed for connection with manually-operable head I59.

In the illustrated embodiment the outer end of e the threaded element I51 has a fluted or ridged configuration and isadapted to receive the head I 59 shrink-fitted thereon.

By operating the head, the threaded member faces of the sleeve.

151 may be tightened into the sleeve, thereby forcing the stem I55 and the clamping block I5'I radially inwardly in order to clampingly engage and secure the portion I53 on a clamp seaton which it is assembled.

I prefer to form the threaded member I51 as an element separate from the stem I55 in order that the same may be readily renewed in 'the event of damage. Projecting elements of this character often become bent in service due to forces accidentally applied on the head'I59 in a direction to cause bending of the projecting portions of the element I51. In order to minimize such mechanical damage to the projecting screw portions, and also to improve the appearance of the instrument, and to house the projecting screw portions: andprotect the same from the deleterious effect of foreign matter, such as atmospheric dirt and moisture, I prefer to form the headl59 to a generally tear-drop configuration,

and to form the headwith a cylindrical socket I 6 I of appreciable depth threaded element I51.

This socket I6I is formed to snugly receive the cylindrical end portions of the sleeve-like frame extension I 53, so that the head I 59 is substantially journalled on'and'supported by the outer sur- By means of this "arrangement, screw bending forces applied on the head are largely absorbed by the extension I53, so that the screw itself is protected against damage through bending. The tear-drop Configuration of the head permits accidental blows to glance off, thus additionally protecting the screw against damage.

supporting sleeve I04.

As shown in Figures 3 and 5, the sleevel53 may extend outwardly of the clamp portion I43 in any desired or convenient direction. 'In Figure 4 of the drawings, however, I have shown the sleeve I53 extending between the clamping portion I 43 and the tangent adjusting means I45, so that the sleeve extension I53 not only serves to support and enclose theclamp actuating stem and screw I55 and I 51 and support the actuating head I59, but also serves to brace and strengthen the clamp frame and to assist in rigidly interconnecting the clamping portion I53 with the-adjusting mechanism I45.

The clamp I3I, shown in Figure 3 of the drawings, is assembled .in the transit on the tilting frame I21, with the portion 'I43 of the clamp mounted on a cylindrical clamp seat concentric with the tilting axis of the frame I21, the clamping portion I43 of the clamp being received between facing shoulders I63 formed adjacent and on opposite sides of the cylindrical clamp seatz The clamp I33 in the transit assembly is mounted with the clamping portion I43 embracing the clamp seat 83, the opposite sides 'of' the clamp around the screw- A similar arrangement may be employed for supporting the stem head I06 on its portion, respectively, engaging the shoulder 8| The clamp 131 of the level is assembled with its clamping portion I43 embracing a cylindrical clamp seat formed in the upper end of thesleeve 33, with the opposite sides of the clamp portion bearing upon facing shoulders formed, respectively, in the frame I39 an-din the sleeve 33.

In each clamp the packing means I31 serves to seal the sliding joint between the clamp portion I43 and the facing shoulders defining the op-- posite sides of the clamp seat, to protect the clamp surfaces from deleterious foreign matter.

The tangent adjusting mechanism in each case comprises cooperating means I45 and I45, respectively, on a pair of relatively angularly movable frames. The cooperating means I55 on one frame comprises a preferably elongated housing I1 I, in the opposite ends of which are mounted tangent adjusting pintles having ends extending oppositely into the interior of the housing. To this end, the pintle supporting housing comprises a pair of spaced apart sleeve portions I13 and I15 in coaxial alignment, with a space I11 between the facing ends of the sleeves. The outer end of the sleeve I13 in each case carries a cover I19 comprising a shell closed at one end, the opposite end being open and threaded into the outer end of the sleeve I13. The shell and sleeve on which it is mounted slidingly receive a pintle element I8I having an end extending into the space I11.

The pintle element I8I is.preferably hollow and fits snugly into the sleeve I13 to form therewith and with the shell I19 a closed, expansible housing containing spring means I83 normally urging the pintle element in a direction toward and into the space I11.

- It will be seen that the foregoing arrangement substantially prevents the entrance of deleterious foreign matter into the expansible housing enclosing the spring I83 which is thus protected against deterioration by the cooperation of the pintle and the shell.

' The sleeve I15 is internally'threaded to receive a threaded stem I having a pointed end extending within the space I11 in opposing alignment with respect to the pintle IIII. The stem I85 extends at its opposite end outwardly of thesleeve I15 and is provided with a manuallyoperable head I81 preferably similar to the head I59, the outer end of the stem I85 being fluted and receiving the head shrink-fitted thereon.

The outer surfaces of the end of the sleeve I 15 are preferably finished to cylindrical form, and the head I81 is provided with a cavity I89 to snugly receive the end of the sleeve in order to substantially journal and support the head on the sleeve in order to enclose and protect the stem against bending and against deleterious foreign matter, as heretofore described in connection with the head I59.

The sleeve I15 may be slit longitudinally, as at I9I, the split portions being interconnected by a clamping element I93 for adjusting the tightness of the sleeve upon the stem I535. The housing I1I is provided with a lateral opening I55 between the facing ends of the sleeves I15 and I15, said opening giving access to the chamber I11 and being defined by edges forming a seat.

The housing HI and the adjusting pintles mounted therein are supported-on one of a pair of relatively movable frame elements, which, in the embodiments illustrated in Figures 1, 2 and 13, ispreferably the frame element having the clamp means I43. Another of said relatively movable frame elements, which, in all of the illustrated embodiments, comprises the frame which is rotatable with respect to the one on which the clamping frame is adjustably mounted, carries the cooperating tangent adjustment means I45 which comprises an extension forming a cover I65 comprising a seat adapted at all times to overlie and form a cover for the opening I95." The housing I1I also is preferably formed with a groove at the opening I in which is mounted a sealing gasket I91 in position to wipe upon the cover or seat I65 and securely seal the opening I95;

As shown in Figures 1-9 and 11-14, each of the clamps I3I, I33, I35 and I31 have frame portions extending outwardly of their respective clamping portions I43 and preferably carrythe tangent adjusting means I45 in position opposite the cover I55 which is formed in a frame elementassociated with and angularly movable with respect to the carrying frame on which the clamp is seated. In

connection with the clamp I3I, the cover I65 is formed on one of the uprights I23. In connection with the clamp I33, the cooperating cover I65 isformed in an extension I61 on and prefer-. ably integral with the compass plate 93 at the marginal edge thereof. In connection with the clamp I35, the cooperating cover IE5 is formed in an extension I59 on and preferably integral with the tilting frame 3I.v In connection with the clamp I31, the cooperating cover I55 is formed on the lower surface of the telescope-carrying frame I39. T

The extension forming the cover or seat I65 also carries a finger I99 extending outwardly of the seat I55 in position to enter the cavity or chamber I11 between the facing ends of the aligned tangent adjusting members I8I and I85. This finger preferably has a hardened insert 2M upon which the opposite ends of the adjusting elements are adapted to bear. The finger I99 is mounted in the seat-forming element in any suitable or preferred manner, preferably by threading the finger in a correspondingly threaded socket arranged in the seat-forming element.

In the embodiments illustrated in Figures 1-9 and 11-14, the housing Il'I is formed as an integral part of the clamp frame, so that the tangent adjusting pintles I8I and I85 are mounted on the clamp, while the finger I99 is carried in a relatively movable frame portion. My invention, however, contemplates and includes a reversal of the cooperating tangent adjusting elements wherein the finger I99 is mounted on and the seat IE5 is formed in the clamp, while the housing III, in which the adjusting pintles are mounted, is attached to the cooperating angularly movable frame element; that is to say, the frame member which is rotatable with respect to the carrying frame on which the clamp frame is adjustably supported. This possibility is shown in Figure 10 in which cooperating means I45, comprising the housing and the pintles mounted therein, is attached to the compass plate, as shown at 253, the housing being preferably formed as an integral extension on the compass plate at the marginal edge thereof, while the cooperating compass plate clamp member is formed, as shown at 295, with the cooperating means I45 comprising the cover for covering the lateral housing opening and the finger I99. In this embodiment theclamp is of simplified construction, the extension I53 which carries the clamp-actuating stemserving also as a support for the cover-forming extension and for thefinger I99. a

In Figures 11 and 12 of the drawings, I have shown a modified arrangement of the clamp I33 wherein the housing III is arranged with the housing opening facing in a direction radially away from the axis of the clamping portion I43, as distinguished from the housing arrangements in which the housing opening faces a direction parallel with respect to the axis of the clamp portion M3, in which the seat I65 may lie in a fiat plane, the edges of the housing opening likewise extendingin a flat plane. i

In-the embodiment shown in Figures 11 and 12,

however, the seat I65 is necessarily curved about I It will be seen, from the foregoing, that the tangent adjusting mechanism, including theoperating ends of the pintles IBI and I85, as'well'as the finger I99, are at all times sealed within the chamber In, so that atmosphericdirt, moisture and other deleterioussubstances are excluded, and deterioration of the accurate adjusting mechanism is prevented. The arrangement of the housing asfan integral part of the frameon which it is mounted not only imparts strength and rigidity to the frame and particularly where the housingforms a part of a clamp frame, but the housing itself interconnects and rigidifies the sleeves in which the tangent adjusting pintles are mounted, so that the pintles are protected against mechanical damage, as well as from displacement and resulting misalignment, the parts being especially well protected against mechanical damage resulting from blows and impact to which devices of the character mentioned are frequently exposed when in service.

Not only is the relativelyidelicate tangent adi justing mechanism entirely housed and protected from deleterious matter and mechanical damage, but the clamps also are rigidified. In addition, the arrangement of the clamp seats, particularly as shown in Figure 2 of the drawings, whereinthe clamps are provided with thesealing gaskets I41 in position to cooperate with the flange I1 and with the shoulders I9 and 8|, insures exclusion of deleterious dirt and moisture from the bearings and journals by means of whichthe relatively rotatable parts are connected together,:said parts being protected against entrance of foreign matter through the lower end thereof by means of the nut 55. So, also, the sealing gaskets I41 in'the clamp I3I prevent foreign matter from reaching'and impairing the interior bearing surfaces of the clamp'and the seat on which it is mounted. 7

It is thought that the invention and numerous of its attendant advantages will be' understood from the foregoing description, and it is obvious, that numerous changes may be made in the form,

construction and arrangement of the several parts without departing fromthe spirit or scope of the 7 members, means forming a housing on'one' of said members having an opening defined by edges forming a cover seat about said opening, means forming an abutment on the other of said members and a cover surrounding said abutment and having a surface in position to slidingly engage said seat, whereby the means forming said cover and said housing may cooperate to provide an enclosure for said abutment, and adjusting means on the housing in position to cooperate with said abutment Within the housing to relatively shift the abutment therein whereby to accurately'ad just the relative position of said members.

2. The combination stated in claim- 1, includ ing resilient gasket means interposed between the seat and cover.

3. The combination stated in claim 1, wherein the frame members are interconnected for relative angular movement about an axis and wherein thesurface of the cover is curved withcenter of curvature at said axis, the cover seat being correspondingly curved.

4. The combination as wherein said adjusting means comprises a stem having an end projecting from a sleeve-like portion of said housing having an annular surface forming a seat encircling said stem, and a head on the projecting portions of said stem and formed with a skirt encircling said projecting portions and having an annular surface interfitting with the annular surface of the sleevelike portion to provide support for said head directly 'on the sleeve-like portion to prevent stem-bendingmovement of the head with respect to the sleeve-like frame portion.

5. In a device of the'clas's described, a frame having a sleeve-like stem supporting portion, a stemsupported in and having a portion projecting from an end of said sleeve-like portion,

said sleeve-like portion having an outwardlyfacing cylindrical seat formed on the end' thereof head directly on the sleeve-like portion to prevent stem-bending movement of the head with respect to the sleeve-like frame portion. i y

6. In a device of the class described, in combination, a pair of relatively shiftable frame members,.means forming a housing on one. of said members having an opening defined by edges forming a cover seat about said opening,

means forming an abutment having oppositely facing shoulders on the other of said members and a cover surrounding said abutment and having a surface in position to slidingly engage said seat, whereby the means forming said cover and said housingmay cooperate to provide an enclosure for said abutment, and adjusting means comprising aligned pintles on. the housing and having facing ends in position to engage said oppositelyfacing shoulders of the abutment within the housing, said pintles being operable to relatively. shift said abutment within said housing whereby to accurately adjust the relative position of said members. r V j '7. In a device of the class described, in com bination, a pair of relatively shiftable frame members and a mounting member, means forming a housing on one of said frame members having an opening defined by edges forming a' cover seat about said opening, means forming an abutment on the other of said frame members member comprising means forming a clamp seat on the mounting member and clamp means on the frame member operable to .adjustably secure set forth in claim 1,

the frame member on said mounting member, and adjusting means on the housing in position to cooperate with said abutment within the housing and operable to accurately adjust the relative position of said frame members.

8. In a device of the class described, in combination, a pair of relatively shiftable frame members and a mounting member, means forming a housing on one of said frame members having an opening defined by edges forming a cover seat about said opening, means forming an abutment on the other of said frame members and a cover surrounding said abutment and having a surface inposition to slidingly engage said seat, whereby the means forming said cover and said housing may cooperate to provide an enclosure for said abutment, cooperating means on one of said frame members and on the mounting member comprising means forming a clamp seat on the mounting member and clamp means on the frame member operable to adjustably secure the frame member on said mounting member, and adjusting means comprising a pintle threaded in and having an end extending within said housing in position to engage said abutment therein and means extending outwardly of said housing to actuate said pintle to move said abutment relatively and within said housing whereby to adjust the relative position of said frame members.

9. In a device of the class described, in combination, a pair of relatively shiftable frame members and a mounting member, means forming a housing on one of said frame members having an opening defined by edges forming a cover seat about said opening, means forming an abutment on one of said frame members and a cover surrounding said abutment and having a surface in position to slidingly engage said seat, whereby the means forming said cover and said housing may cooperate to provide a closure for said abutment, cooperating means on one of said frame members and on the mounting member and-comprising means forming a clamp seat on the member and clamp means on the frame member operable to adjustably secure the frame member on said mounting member, and adjusting means on the housing in position to cooperate with said abutment within the housing and operable to accurately adjust the relative position of said frame members, and manually-operable means for actuating said clamp means and said adjusting means and comprising stems having manually-operable heads positioned in adjacent relationship in the assembly to facilitate operation of both heads from a common manipulative position.

10..In a device of the class described, in combination, a pair of relatively shiftable frame members and a mounting member, means forming a housing on one of said frame members having an opening defined by edges forming a cover seat about said opening, means forming an abutment on one of said frame members and a cover surrounding said abutment and having a surface in position to slidingly engage said seat around said abutment whereby the means forming said cover and said housing may cooperate to provide a closure for said abutment, cooperating means on one of said frame members and on the mounting member and comprising means forming a clamp seat on the mounting member and clamp means on the frame member operable to adjustably secure the frame member on said mounting member, adjusting means on the housing in position to cooperate withsaid abutment within the housing and operable to accurately adjust the relative position of said frame members, manually-operable means comprising a clamp actuating stem carried, in the frame member having the clamp means and extending therein, substantially adjacent said abutment,

and additional manually-operable means comprising an adjusting screw extending, in the ing an opening defined by edges forming a cover seat about said opening, means forming an abutment on the other of said frame members and a cover surrounding said abutment and having a surface in position to slidingly engage said seat,

whereby the means forming said cover and said housing may cooperate to provide an enclosure for said abutment, cooperating means on the frame member having the housing and on the mounting member comprising means forming a clamp seat on the mounting member and clamp means on the frame member operable to adjustably secure the frame memberon said mounting member, manually-operable means for actuating the clamp means comprising a stem supported in said frame and having a manually-operable head adjacent said housing, and adjusting means carried by the housing in position to cooperate with said abutment within the housing and comprising a stem having a headed end extending outwardly of said housingin a direction substantially normal to the clamp actuating stem.

12. In a device of the class described, in combination, a pair of relatively shiftable frame-members and a mounting member, means forming a housing on one of said frame members having an opening defined by edges forming a cover seat, means forming an abutment on the other frame member and a cover surrounding said abutment in position to slidingly engage said seat, whereby said cover and said housing cooperate to provide an enclosure for said abutment, cooperating means on the frame member having the abutment and cover and on the mounting member comprising means forming a clamp seat on the mounting member and clamp means on the frame member operable adjustably to secure the frame member on said mounting member, said clamp means comprising a clamp actuating stem supported in the frame member and extending in alignment with said abutment, said stem having an end projecting from said frame member beyond andadjacent said abutment and its enclosing housing, a manually-operable head on the "projecting end of said stern, adjusting means on'the housing in position to cooperate with said abutment therein and comprising a stem having an end projecting from said housing and provided with a manuallyoperable head adjacent the head on said clamp actuating stem. I a

13. In a device of the class'described, in combination, a pair of relatively shiftable frame mem-' bers and a mounting member, means forming a housing on one of said frame members having an opening defined by edges forming a cover seat about said opening, means forming an abutment on one of said frame members and a cover surrounding said abutment and having a surface in position to slidingly engage said seat, whereby prising means forming a clamp seat on the member and clamp means on the frame member operable to adjustably secure the frame member on saidmounting member, and adjusting means on the housing in position to cooperate with said abutment within the housing and operable to accurately adjust 'the relative position of said frame members, and manually-operable means for actuating said clamp means and said adjusting means and comprising stems each extending in and having an end projecting from a sleeve-like frame portion,-said sleeve-like portion having an annular surface forming a seat encircling the stem therein, and a head on the projecting portion of the stem and formed with'a skirt enclosing saidprojecting-portion and having an annular surface interfitting with the annular surface of the sleeve-like frame portion to provide support for said head directly'on' the frame portion to prevent stem-bending movement of the head with respect to the frame portion.

14. In a surveying instrument, in combination, a mounting member, a pair of frame members mounted for relative angular movement with respect to said mounting member about a common axis, cooperating adjusting means comprising means forming a housing on one of said frame members having an opening defined by edges forming a cover seat about said opening, means forming an abutment on 'said other frame member and a cover surrounding said abutment and forming a surface adapted to slidingly engage said peripheral seat, whereby the means forming said cover and said housing may cooperateto provide an enclosure for said abutment, cooperating means on one of said frame members and on the mounting member comprising means forming a clamp seat on the mounting member andclamp means on the frame member operable to adjustably secure the frame member on said mounting member, adjusting means .on the housing in position to cooperate with said abutment to adjustably shift the same within the housing whereby ,to' accurately adjust the relative angular position of said frame members, and means for supporting a sighting device on one of said members.

15. A surveying instrument as set forth in claim 14, wherein one of said frame members comprises a base forming a journal and associated means 1 for leveling said base, while the mounting member comprises a clamp carrying frame having a sleeve rotatable in said journal with an end projecting therefrom and formed with a pair of adjacent clamp seats defined between shoulders formed on said frames, the other of said frame members comprising a cla'mpframe embodying theclamp means and mounted in clamp-ing relationship on one of said clamp seats formed in said clamp-carrying frame between shoulders,

' respectively, on the base and on the clampcarrying frame, said adjusting means being cooperatively associated with said baseand clamp frame, the means forsupporting said sighting device comprising a support frame having a portion journalled for rotation in said sleeve, and an additional clamp frame having a clamping portion on the other of said clamp seats between shoulders formed on the clamp-carrying frame, cooperating means on said additional clamp and support frames comprising an abutment on one and a housing on the other enclosing said abutment, and means mounted on the housing for shifting the abutment therein whereby to angularly adjust the additional clamp and support frames, and resilient gasket-means on the opposedsaid plate, said mounting member, in addition to the clamp seat, carrying means forming an annular seat between'the clamp seat and said plate,

an annular cover member sealed on said seat and having peripheral edges extending to and interfitting with the peripheral flange of said plate, and a packing material interposed between said interfitting marginal flanges. 7

1'7. A surveying instrument as set forth in claim 14, wherein one of said members comprises a support frame or base and another of the members comprises a carrying frame formed to support means for mounting a sighting device on the carrying frame, the frame member having the clamp means serving to adjustably secure the support frame'and carrying frame in a desired relative angular relationship, and means for leveling the support frame or base. 7

18. In a surveying instrument, comprising a support and instrument carrying means rotatable on the support, the combination with said support and said carrying means of projecting means on said support and extending to an edge of said carrying means, tangent adjusting means on said 'support in position to operatively engage said ment and a carrying element for a sighting device pivoted for relative angular movement about'a common axis, a clamp element having an annular part encircling one of said relatively pivoted elements wherebyv the clamp is relatively and angularly adjustable with respect to the element on which it is mounted on said common axis, meansmanually operable to clamp said annular part in adjusted angular position with respect to said element, said clamp having integral projecting portions carried by and extending from said'annular part oppositea remote portion, of. the other relatively pivoted element, a-projecting finger integral with one ofsaid portions, said other portion having integral means forming alined sleeves having facing ends in spaced abuttingrrelationship, said integral means including a lip laterally enclosing the sides of the space between the abutting ends of the sleeves to form a compartment in which said finger extends between the abutting ends of .the sleeves, and tangent adjusting means comprisingpintles in said sleeves and having ends extending in said compartment in position to engage opposite sides of said finger, one of said pintles being screw- .threadedin its corresponding sleeve and projecting ,outwardlyof the end of said sleeve opposite from the chamber and formed with manually operable means on its outwardly projecting portions for adjusting its position in the sleeve, and the other pintle being yieldingly pressed toward and into engagement with said finger to keep the finger in yielding engagement with the threaded pintle.

20. In a surveying instrument as set forth in claim 19, the combination wherein the projecting finger is formed with integral means in position to slidingly cooperate with said lip to close the chamber regardless of the relative position of the finger within the chamber and between the facing ends of said sleeves.

21. In a surveying instrument as set forth in claim 19, the combination wherein said lip encloses at least three sides of the space between the abutting ends of the sleeves, and forms a trough for simultaneously receiving the finger in all of its adjusted positions between the facing ends of the sleeves.

22. In a surveying instrument as set forth in claim 19, the combination wherein the manually operable means for clamping the annular part :of the clamp upon the element upon which it is mounted comprises a stem threaded in said clamp and extending from the annular part thereof in a channel formed in the projecting portion of the clamp, said stem having an end extending outwardly of the end of said projecting portion adjacent the remote portion of the other relatively pivoted element and formed with manually operable means on its outwardly extending end for controlling the clamp whereby said manually operable clamp controlling means is disposed adjacent the manually operable tangent adjusting means.

23. In a surveying instrument as set forth in claim 19, the combination wherein the projecting portions of said clamp comprise a pair of spaced arms extending outwardly of said annular part, each of said arms terminating in one of said alined sleeves whereby said clamp is constituted as a rigid, rugged frame carrying not only the manually operable clamp means but also the tangent adjusting means, including the alined sleeves carrying the pintles as well as the integral lip interconnecting said sleeves and forming the finger receiving trough or chamber.

24. In a surveying instrument comprising a support, a rotatable compass plate on said support and having integral means at the peripheral portions of said plate forming a dependent lip support and instrument-carrying means rotatable on the support, the combination with said support and said carrying means of a clamp comprising an annular portion encircling said instrument-carrying means, means to secure said annular portion fast on said instrument-carrying means, said annular portion having a pair of integral arms extending outwardly thereof, the ends of said arms being formed with integral sleeve-like portions in axial alignment, said support being formed with a finger extending between the facing ends of said sleeve-like portions, integral meansrigidly interconnecting said sleeve-like portions and forming a housing enclosing said finger, and pintles carried by each sleeve and having ends extending therefrom within said housing and in position to engage opposed sides of said finger.

26. In a surveying instrument comprising a support standard and an instrument-carrying axle rotatable on said standard, the combination with said standard-and said carrying axle, of a clamp comprising an annular portion encircling said axle, means to secure said annular portion fast on said axle, said annular portion having a pair of integral arms extending outwardly thereof tangentially, the ends of said arms being formed with integral sleeve-like portions in axial alignment, said standard being formed with an outstanding finger extending between the facing ends of said-sleeve-like portions, integral means rigidly interconnecting said sleeve-like portions and forming a trough-like housing enclosing said finger, and pintles carried by each sleeve and having ends extending therefrom within said housing in position to engage oppositesides of said finger.

2'7. A surveying instrument as set forth in claim 14, wherein the member having the clamp seat comprises a support frame or base and an other of the members comprises a carrying frame formed to support means for mounting a sighting device on the carrying frame, the frame member having the clamp means serving to adjustably secure the support frame and carrying frame in a desired relative angular relationship, and means for leveling the support frame or base.

28. A surveying instrument as set forth in claim 14 wherein the member having the clamp seat comprises a carrying frame formed to sup port means for mounting a sighting device on the carrying frame while another of the members comprises a support frame or base, the frame member having the clamp means serving to adjustably secure the support frame and carrying frame in a desired relative angular relationship, and means for leveling the support frame or base.

29. A surveying instrument as set forth in claim 14, wherein one of the members comprises a carrying frame adapted to support means for mounting a sighting device, another of said members comprises a support frame or base in which the carrying frame is journalled for rotation, and wherein the means forming the abutment enclosing housing is on the member having the clamp, the abutment and cover being on one of the other members.

30. A surveying instrument asset forth in claim 14, wherein one of the members comprises a carrying frame adapted to support means for mounting a sighting device, another of said members comprises a support frame or base in which the carrying frame is journalled for rotation, and wherein the means forming the abutment enclos ing housing is on the member having the clamp, the abutment and cover, being on the carrying frame.

31. A surveying instrument as set forth in claim 14, wherein one of the members comprises a carrying frame adapted to support means for mounting a sighting device, another of said members comprises a support frame or base in which the carrying'frame is journalled for rotation, and wherein the means forming the abutment enclosing housing is on the member having the clamp, the abutment and cover being on the support frame or base.

32. A surveying instrument as set forth in 7 claim 14, wherein one of the members comprises a carrying frame adapted to support means for mounting a sighting device, another of said members comprises a support frame or base in which the carrying frame is journalled for rotation, and wherein the means forming the abutment and housing cover is on the frame member having the clamp, the abutment enclosing housing being on one of the other members.

33. A surveying instrument as set forth in claim 14, wherein one of the members comprises a carrying frame adapted to support means for mounting a sighting device, another of said members comprises a support frame or base in which the carrying frame is journalled for rotation, and

wherein the means forming the abutment and housing cover is on the frame member having the clamp, the abutment enclosing housing being on the carrying frame. I

34. A surveying instrument as set forth in claim 14, wherein one of the members comprises a carrying frame adapted to support means for mounting a sighting device, another of said members comprises a support frame or base in which the carrying frame is journalled for rotation, and wherein the means forming the abutment and housing cover is on the frame member having the clamp, the abutment enclosing housing being on the support frame or base.

35. A device of the class described comprising a frame element formedwith a bearing, a support member in said bearing, means mounting a sighting device for rotation with said support member, means on said member comprising a projecting element, means on one of said elements forming a chamber having an opening and the other element having a finger portion extending intothe chamber through said opening and having a bearing portion disposed within the chamber, a stem threaded in a wall of said chamber at one end thereof in position to engage one side of said bearing portion, means-extending outwardly'of said chamber and manually operable to turn said stem, means in the walls of said chamber at the opposite end thereof and having a presser portion extending in said chamber on the opposite side of said bearing portion, and means yieldingly urging said presser portion toward the bearing portion whereby tohold the same in engagement with said stem so that by adjusting the stem the relative angular position of said finger about the axis of said support member with respect to the element having the chamber may be critically adjusted.

36. A device of the class described, comprising a pair of frame elements interconnected for relative rotational movement, one of the elements forming a support for the other, and said other element carrying means forming a mounting for a sighting device, and means to adjust the angular relationship of the elements comprising chamber forming means on one of said elements providing an enclosing chamber having a lateral opening, means on the other element comprising a finger in position extending in said chamber through said opening and having a bearing portion within said chamber, and adjusting means on said chamber-forming means and cooperatively associated with said bearing portionwithin the chamber for shifting said finger therein to adjust the relative angular relationship of the said frame elements.

37. A device of the class described, comprising a pair of frame elements interconnected for relative rotational movement, one of the elements forming a support for the other, and said other element carrying means forming a mounting for a sighting device, spirit level means supported by said mounting element, and means to adjust the angular relationship of the elements comprising chamber-forming means on one of said elements providing an enclosing chamber having a lateral opening, means on the other element comprising a finger in position extending in said chamber through said opening and having a bearing portion within said chamber, and adjusting means on said chamber-forming means and. cooperatively associated with said bearing portion within the chamber for shifting said finger therein to adjust the relative angular relationship of the said frame elements. 7

38. A device of the class described, comprising a pair of frame elements interconnected for relative rotational movement, one of said elements supporting the other and said other element forming a mounting for a sighting device, and means to adjust the relative angular relationship of the elements comprising a clamp member and means to clamp the same on one of said elements, said clamp having an outwardlyextending portion, and the other element having a cooperating portion adapted for cooperation comprising chamber-forming means providing a chamber having a lateral opening, and the other portion comprising a finger in position extending in said chamber through said opening and having a bearing portion within said chamber, and adjusting means on said chamber-forming means and cooperatively associated with said bearing portion within the chamber for shifting 'with'said extending portion, one of said portions said finger therein to adjust the relative angular relationship of the said frame means.

' ADOLPI-I LANGSNER. 

